Elastomers are typically compounded with fillers, crosslinking agents and other additives, followed by forming or shaping into the desired configuration for the article to be made from the elastomer. This forming can be by calendaring or extrusion, but most often is done by compression or injection molding. After shaping, the elastomer molecules are crosslinked by the action of the crosslinking agents to establish a three-dimensional structure that provides strength and form stability. Such crosslinking, or curing, is usually effected by heat and time. An elastomer is often first press-cured at an elevated temperature and pressure when confined in a mold, and then post-cured at elevated temperatures and ambient pressures for an additional period to complete the curing.
Many elastomers can be cured in relatively short periods, while other elastomers, and particularly fluoroelastomers and ethylene/acrylic elastomers, require several hours for full development of the desired mechanical and aging properties of the finished product. Since these properties are dependent on the completion of this curing or postcuring process, techniques have previously been developed to test the degree of curing in an elastomeric composition. Such techniques have heretofore often required time-consuming destructive physical testing of lot samples.